Interfacial Hydroxyl Promotes the Reduction of 4-Nitrophenol by Ag-based Catalysts Confined in Dendritic Mesoporous Silica Nanospheres

Surface states - the electronic states found in a solid material that terminate at a surface - are usually vulnerable to contamination and defects. This fundamental limitation has prohibited systematic studies of the potential role of surface states in surface reactions and catalysis, especially in more realistic environments. We use the selective reduction of 4-nitrophenol on silver-covered dendritic mesoporous silica nanospheres as a prototype example and show that the dynamic intermediate surface states (DISSs) spatially formed by atomic orbital overlapping in singly hydrated hydroxyl complexes on the confined nanoscale interface of Ag nanoparticle could act as alternative reaction channels for high-rate reduction of 4-nitrophenol by promoting different directions of static electron transfer. The concept of DISS as an electron pool may lead to new design principles beyond the conventional d-band theory of heterogeneous catalysis.